I Date Dead People is the fifth entry in the "My Boyfriend is a Monster" graphic novel series. I got it as an ARC at a conference at least 10 years ago.
This review includes spoilers.
Review:
Nora's family has recently moved into a beautiful old house previously Eleanor Hays, a famous author. Although her younger siblings make some odd comments and several items go missing, Nora doesn't realize there's anything odd about her new home until she's home alone one evening and meets a ghost. It initially scares her, but Tom, the ghost, doesn't seem all that bad - he returns the stuff he took and just asks that Nora's family not remove the house's grandfather clock. However, he's not the only ghost haunting the house, and a couple of the others aren't nearly so nice.